The Union flag, is known as the Stars and Stripes, symbolized solidarity and patriotism

https://cruzbuxy751.solsticebrief.com/posts/reenactment-essentials-must-have-civil-war-flags-for-authentic-experiences-3

The Union flag, is known as the Stars and Stripes, symbolized solidarity and patriotism, providing thirteen stripes and a field of blue with stars that represented both state in the union.